JP2008006592A - Method for producing sheet-shaped product of polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily producing a sheet-shaped product of polyurethane foam in which powder falling in an end surface and a thickness change are suppressed. <P>SOLUTION: The raw material 15 of the polyurethane foam containing a polyol, a polyisocyanate, a catalyst, and a blowing agent is supplied from the supply port 16 of a raw material feeding apparatus 17 onto a resin film 12. From a delivery roller 18, a release film 19 is mounted on the raw material 15. As the polyol, a polyether polyol having a primary hydroxyl group at the end with its ratio being at least 50 mass% is used, and a temperature-sensitive catalyst is used as the catalyst. The raw material 15, while placed between the resin film 12 and the release film 19, is passed through the primary and secondary passages 23 and passage 24 of a heating furnace, reacted, expanded, and cured. After that, the sheet-shaped product 10 can be produced by peeling the release film 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a sheet product of polyurethane foam used as a gasket (packing) for absorbing noise generated from, for example, a hard disk of a computer, a mobile phone, etc., or imparting sealing properties. It is.

  The applicant of the present application has already proposed this type of sheet-like product. For example, after applying a reaction mixture containing polyol, polyisocyanate and catalyst on a release sheet, heating to react and cure, and placing a base material made of foam on the surface of the reaction mixture in the middle of curing The laminate is obtained by completing the curing of the reaction mixture and forming a cured film of the reaction mixture on the surface of the substrate (see Patent Document 1). This laminate is used as a waterproof sealing material or the like, and by changing the size of the release sheet, products having different sizes can be easily manufactured, and products having a constant surface shape can be obtained. .

In addition, a resin film is bonded to at least one surface of a sheet made of polyurethane foam, and the amount of elution when a component having a melting point of 100 ° C. or less contained in the sheet is extracted with acetone by Soxhlet extraction for 8 hours is 1 It is a polyurethane foam sheet-like product having a mass% or less (see Patent Document 2). According to this sheet-like product, blocking that adheres when stacked can be prevented.
JP2003-225913A (pages 2 and 4) JP-A-10-83667 (2nd page, 4th to 6th pages)

  By the way, the above-mentioned gasket is generally formed by punching a sheet-like product with a Thomson mold or the like. In this case, the polyurethane foam used in the sheet-like product described in Patent Documents 1 and 2 is a foam, so that powder falls from the processed end face after punching. When powder falls, the powder contacts an electronic component substrate, causing an electrical short circuit. For this reason, it is necessary to prevent powder from falling off at the end face of the sheet-like product.

  Furthermore, when the sheet-like product described in Patent Document 1 is continuously produced, the reaction is accelerated because the polyurethane raw material is heated and reacted and cured, and the thickness of the cured film formed by the reaction mixture is increased. The tendency to become thick gradually is shown. In addition, when the sheet-like product described in Patent Document 2 is continuously produced, the reaction is accelerated because the catalyst for obtaining the polyurethane foam is a combination of an amine catalyst and a metal catalyst. The body thickness tends to increase gradually. As described above, when the thickness of the sheet-like product changes, the thickness accuracy required as a part of the electronic device is not satisfied, and the product becomes inappropriate.

  Accordingly, an object of the present invention is to provide a method for producing a sheet product of polyurethane foam, which can easily produce a sheet product in which powder fall off at the end face is suppressed and the change in thickness is suppressed. It is to provide.

  In order to achieve the above object, a method for producing a polyurethane foam sheet-like product according to claim 1 comprises a polyurethane foam containing a polyol, a polyisocyanate, a catalyst and a foaming agent on a resin film. A polyurethane foam sheet-like product in which a polyurethane foam sheet is formed by reacting a polyol and a polyisocyanate, foaming and curing, and a resin film adhered to the sheet is manufactured. In this case, as the polyol, a polyether polyol having a primary hydroxyl group at the terminal and a ratio of 50% by mass or more is used, and a temperature-sensitive catalyst is used as a catalyst.

  The method for producing a polyurethane foam sheet-like product according to claim 2 is the triol obtained by adding propylene oxide and ethylene oxide to a trihydric alcohol in the invention according to claim 1. It is characterized by being.

  A method for producing a polyurethane foam sheet-like product according to claim 3 is the invention according to claim 1 or 2, wherein the temperature-sensitive catalyst is a diazabicycloalkene or a salt thereof. It is a feature.

  According to a fourth aspect of the present invention, there is provided a method for producing a polyurethane foam sheet-like product according to any one of the first to third aspects, wherein a release film is formed on the raw material of the polyurethane foam. The release film is peeled off after being put on, reacted with polyols and polyisocyanates, foamed and cured.

  The method for producing a polyurethane foam sheet-like product according to claim 5 is the invention according to any one of claims 1 to 4, wherein the polyurethane foam sheet-like product is for electronic equipment. It is a thing used as a gasket of this.

According to the present invention, the following effects can be exhibited.
In the method for producing a polyurethane foam sheet-like product according to the first aspect of the present invention, a polyether polyol having a primary hydroxyl group at the terminal and a proportion of 50% by mass or more is used as the polyol. Since the primary hydroxyl group bonded to the end of the polyether polyol has a better resinization reaction than the secondary hydroxyl group, the resinization reaction proceeds sufficiently, and the resulting polyurethane foam has a dense structure. become. Therefore, powder fall off at the end face of the sheet-like product can be suppressed. Furthermore, since the temperature-sensitive catalyst is used as the catalyst, the resinification reaction proceeds slowly and uniformly with increasing temperature, and the change in thickness of the sheet-like product can be suppressed. Therefore, by selecting the polyols and the catalyst in the raw material of the polyurethane foam as described above, a sheet-like product having the above effects can be easily produced.

  In the method for producing a polyurethane foam sheet-like product according to claim 2, the polyether polyol is a triol obtained by adding propylene oxide and ethylene oxide to a trihydric alcohol. Can increase density and strength. Therefore, in addition to the effect of the invention according to claim 1, powder fall off at the end face of the sheet-like product can be further suppressed.

  In the method for producing a polyurethane foam sheet-like product according to claim 3, since the thermosensitive catalyst is a diazabicycloalkene or a salt thereof, it is sensitive to temperature and excellent in temperature sensitivity. . Therefore, in addition to the effect of the invention according to claim 1 or claim 2, the thickness change of the sheet-like product can be further suppressed.

  In the method for producing a polyurethane foam sheet-like product according to claim 4, the release film is placed on the polyurethane foam raw material, the polyols and polyisocyanates are reacted, foamed and cured. Thereafter, the release film is peeled off. For this reason, in addition to the effect of the invention according to any one of claims 1 to 3, a cured film can be formed on the surface portion of the sheet-like product to smooth the surface, and the sheet-like product In the manufacturing process, for example, it can be avoided that the raw material of polyurethane foam adheres to the roller and causes a problem.

  In the method for producing a polyurethane foam sheet-like product according to claim 5, the polyurethane foam sheet-like product is used as a gasket for electronic equipment. Therefore, when manufacturing a gasket for an electronic device, there is no powder falling off at the end face, the thickness change can be suppressed, and the gasket can be easily manufactured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments that are considered to be the best of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 2, a polyurethane foam (hereinafter also simply referred to as a foam) sheet-like product 10 of this embodiment has a resin film 12 bonded to one side (lower surface) of a sheet 11 made of polyurethane foam. It is configured. The sheet-like product 10 is used, for example, by being sandwiched between an electronic component, specifically, a main body of a hard disk drive and a substrate in a computer. Therefore, the thickness of the sheet-like product 10 is preferably 5 mm or less, and more preferably 0.5 to 3 mm. Moreover, it is preferable that the sheet | seat 11 which consists of a polyurethane foam is formed with the open-cell type soft polyurethane foam. Compared to closed cells, sound is effectively absorbed in open cells, and sound propagation can be reduced to improve sound absorption. Furthermore, the surface of the foam is smoothened by forming a film (skin layer) having a thickness of about 2 to 50 μm with a cured product of the soft polyurethane foam in the vicinity of both surfaces of the sheet 11. be able to.

Such a polyurethane foam sheet-like product 10 can be continuously produced as follows.
FIG. 1 is a schematic sectional view showing an apparatus for producing a polyurethane foam sheet product 10. As shown in the figure, a feeding roller 14 around which a resin film 12 is wound is disposed at a rear position (left position in FIG. 1) of the apparatus body 13, and the apparatus body in which the resin film 12 is positioned forward. 13 (two-dot chain line in FIG. 1). As resin which forms the resin film 12, what has adhesiveness with the sheet | seat 11 of polyurethane foams, such as a polyethylene terephthalate (PET), an acrylic resin, a polyamide resin, is used suitably.

  A raw material supply device 17 for discharging a polyurethane foam raw material 15 (liquid) from a supply port 16 opened downward is disposed above the feed roller 14. And the raw material 15 discharged from the supply port 16 of the raw material supply apparatus 17 is supplied on the resin film 12 sent out from the sending-out roller 14. A delivery roller 18 is disposed above the raw material supply device 17, and a release film 19 is wound thereon. As the resin for forming the release film 19, a fluororesin, a silicone resin, or the like is used. The release film 19 delivered from the delivery roller 18 covers the surface of the polyurethane foam material 15 supplied from the material supply device 17. A presser roller 20 is disposed in front of the raw material supply device 17, and is pressed from the upper surface of the release film 19 with the polyurethane foam raw material 15 sandwiched between the resin film 12 and the release film 19. In addition, the thickness between the resin film 12 and the release film 19 is adjusted.

  A primary heating furnace 21 constituting the apparatus main body 13 is provided at a front position of the press roller 20, and a secondary heating furnace 22 similarly constituting the apparatus main body 13 is provided in parallel at the front position. A primary passage 23 is formed through the primary heating furnace 21, and low-temperature heating air of 25 to 40 ° C. is blown onto the sheet 11 passing through the primary passage 23. A secondary passage 24 is formed through the secondary heating furnace 22, and high-temperature heated air of 50 to 150 ° C. is blown onto the sheet 11 passing through the secondary passage 24. In this embodiment, the primary heating furnace 21 is set to 30 ° C., and the secondary heating furnace 22 is set to 80 ° C. Then, foaming is started when the polyurethane foam raw material 15 sandwiched between the resin film 12 and the release film 19 passes through the primary passage 23, and then mainly when the secondary passage 24 passes through the foaming reaction. And the resinification reaction proceeds. Through this process, the resin film 12 is bonded to one surface (lower surface) of the polyurethane foam sheet 11.

  A support roller 25 is disposed at a front position of the secondary heating furnace 22 and is fed forward in a state where the sheet 11 fed from the secondary heating furnace 22 is supported. On the other hand, a winding roller 26 for winding the release film 19 on the heat-treated sheet 11 is disposed above the front end of the secondary heating furnace 22. And the release film 19 on the sheet | seat 11 which came out of the secondary heating furnace 22 is peeled, and it winds up by the winding roller 26, and the sheet-like product 10 with which the resin film 12 was adhere | attached on the lower surface of the sheet | seat 11 is a support roller. 25 is continuously guided forward.

  The polyurethane foam raw material 15 contains polyols, polyisocyanates, a catalyst and a foaming agent, and if necessary, contains other components such as a foam stabilizer. As the polyol, a polyether polyol having a primary hydroxyl group at the terminal and having a proportion of 50% by mass or more, preferably 55 to 90% by mass is used. This is because the terminal primary hydroxyl group has good reactivity with polyisocyanates and the like, and the resinification reaction and the like are promoted. As the polyols, other polyether polyols or polyester polyols can be used as long as the above conditions are satisfied. When the proportion of the terminal primary hydroxyl group in the polyether polyol is less than 50% by mass, the polyether polyol lacks the reactivity with polyisocyanates and the like, and particularly the strength at the end of the sheet-like product 10 becomes weak, and the denseness Therefore, powder fall off at the end face occurs.

  As such a polyether polyol, a polyether polyol made of a polymer obtained by addition-polymerizing propylene oxide and ethylene oxide to polyhydric alcohol, polypropylene glycol, polytetramethylene glycol or the like, a modified product thereof, or the like is used. Examples of the polyhydric alcohol include trihydric alcohols such as glycerin and trimethylolpropane, and dihydric alcohols such as dipropylene glycol. By using a trihydric alcohol, the crosslinking density of a polyurethane foam can be raised and the intensity | strength can be improved.

  Specifically, the polyether polyol is a triol obtained by addition polymerization of propylene oxide and ethylene oxide to glycerin, a triol obtained by addition polymerization of propylene oxide and ethylene oxide to trimethylolpropane, and has a primary hydroxyl group at the terminal, The ratio is 50% by mass or more.

  Other polyether polyols include triols obtained by addition polymerization of propylene oxide to glycerin (the proportion of terminal primary hydroxyl groups is 0% by mass), and triols obtained by addition polymerization of propylene oxide and ethylene oxide to glycerol (the proportion of terminal primary hydroxyl groups is 50%). And a diol obtained by addition polymerization of propylene oxide and ethylene oxide to dipropylene glycol (the ratio of terminal primary hydroxyl groups is less than 50% by mass).

  The polyester polyol is a condensed polyester polyol obtained by reacting a polycarboxylic acid such as adipic acid or phthalic acid with a polyol such as ethylene glycol, diethylene glycol, propylene glycol or glycerin, as well as a lactone polyester polyol and A polycarbonate type polyol is mentioned. When the other polyether polyol or polyester polyol is used, the blending amount may be set so that the ratio of the terminal primary hydroxyl group is 50% by mass or more in the mixture with the polyether polyol satisfying the above conditions. is necessary.

  Polyisocyanates to be reacted with polyols are compounds having a plurality of isocyanate groups, specifically, tolylene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), Triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), or modified products thereof are used. Examples of modified products include MDI prepolymers and polymeric MDI.

  Here, the isocyanate index (isocyanate index) of the polyisocyanates is preferably 80 to 130, and more preferably 100 to 120. Here, the isocyanate index represents the equivalent ratio of the isocyanate group of the polyisocyanate to the active hydrogen such as the hydroxyl group of the polyol and the foaming agent (water) as a percentage. Therefore, when the value is less than 100, it means that the hydroxyl group is in excess of the isocyanate group, and when it exceeds 100, it means that the isocyanate group is in excess of the hydroxyl group. When the isocyanate index is less than 80, the polyols cannot sufficiently react with the polyisocyanates, and the flexibility of the foam is large and the shape retention is reduced. On the other hand, when the isocyanate index exceeds 130, the foam becomes too hard, and the physical properties as a flexible polyurethane foam deteriorate.

  Next, the catalyst is for accelerating a reaction such as a resinification reaction between polyols and polyisocyanates. As such a catalyst, a temperature-sensitive catalyst capable of exhibiting a catalytic function depending on temperature conditions, particularly a temperature-sensitive catalyst capable of exhibiting a catalytic function when heated to 60 to 150 ° C. is used. Such temperature-sensitive catalysts include block catalysts in which an amine catalyst is partially or wholly neutralized with a carboxylic acid, a thermally active catalyst that is normally sealed and heated to form an amine catalyst, and a three-dimensional molecular structure by heating. Examples thereof include a temperature-sensitive catalyst whose catalytic activity is increased by reducing obstacles, approaching electron pairs to nitrogen atoms, and reducing hydrogen bonds.

Specifically, amidinos such as 1,8-diazabicyclo (5.4.0) undecene-7 (DBU) and 1,5-diazabicyclo (4.3.0) nonene-5 (DBN) are used as the temperature-sensitive catalyst. In addition to diazabicycloalkene having a group [H ₂ NC (═NH) —] or a salt thereof, triethylenediamine, a mixture of triethylenediamine and polypropylene glycol, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl Examples thereof include imidazoles such as -2-methylimidazole. Of these, diazabicycloalkene having high catalytic activity or a salt thereof such as phenol salt or octylate is preferred as the temperature-sensitive catalyst.

  As the catalyst, in addition to the above temperature-sensitive catalyst, other amine catalysts, metal catalysts, and the like can be used. Examples of the amine catalyst include tertiary amines such as dimethylethanolamine and N, N ′, N′-trimethylaminoethylpiperazine. Examples of the metal catalyst include organometallic compounds such as tin octylate and alkali metal alcoholates. Of the other catalysts, the combined use of a temperature-sensitive catalyst and another amine catalyst is desirable for allowing the resinification reaction and the foaming reaction to proceed in a well-balanced manner and obtaining a good polyurethane foam.

  The compounding amount of the catalyst is 0.05 to 0.5 parts by mass in the case of a temperature-sensitive catalyst, 0.05 to 1.0 part by mass in the case of an amine catalyst, and 0 in the case of a metal catalyst with respect to 100 parts by mass of polyols. It is preferable that it is 0.05-0.5 mass part. When the blending amount of the temperature-sensitive catalyst is less than 0.05 parts by mass, the function of the temperature-sensitive catalyst cannot be sufficiently obtained, and the temperature dependency of the catalyst is lowered. On the other hand, when the amount exceeds 0.5 parts by mass, the temperature-sensitive catalyst becomes excessive and the resinification reaction tends to be promoted excessively when the temperature rises, which is not preferable. When the compounding amount of the amine catalyst is less than 0.05 part by mass, the resinification reaction becomes insufficient, and when it exceeds 1.0 part by mass, the resinization reaction tends to be excessively promoted, which is not preferable. When the blending amount of the metal catalyst is less than 0.05 parts by mass, the resinification reaction tends to be insufficient, and when it exceeds 0.5 parts by mass, the progress of the resinization reaction tends to be excessive.

  The foaming agent is for foaming polyurethane into a polyurethane foam. As the foaming agent, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide, etc. are used in addition to water. Among these foaming agents, water that is excellent in the reactivity of the foaming reaction and has good handleability is preferable. The blending amount of the foaming agent is preferably 0.1 to 3.0 parts by mass and more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyols. When the blending amount is less than 0.1 parts by mass, foaming becomes insufficient, and when it exceeds 3.0 parts by mass, foaming becomes excessive, both of which are polyurethanes having a desired foaming amount (apparent density). It becomes difficult to obtain a foam.

  As the raw material 15 of the polyurethane foam, a foam stabilizer, an antistatic agent, a flame retardant, an antioxidant, a plasticizer, an ultraviolet absorber, a colorant and the like can be blended in addition to the raw materials 15 described above. As the foam stabilizer, a silicone compound such as dimethylpolysiloxane is used. As the antistatic agent, a cationic surfactant, a nonionic surfactant, or the like is used. As the flame retardant, halogenated phosphate ester, condensed phosphate ester and the like are used.

  Then, the polyurethane foam raw material 15 is foamed, reacted and cured to produce a soft polyurethane foam, but the reaction at that time is complicated, and basically the following reaction is the main component. That is, the addition polymerization reaction between polyols and polyisocyanates and the resinification reaction including the crosslinking reaction between the reaction products and the polyisocyanates, and the foaming reaction between the polyisocyanates and water as a blowing agent. It is believed that there is.

  When the polyurethane foam is produced, a one-shot method or a prepolymer method is employed. The one-shot method is a method in which polyols and polyisocyanates are directly reacted. The prepolymer method is a method in which a part of a polyol and a polyisocyanate are reacted in advance to obtain a prepolymer having an isocyanate group or a hydroxyl group at a terminal, and the polyol or the polyisocyanate is reacted therewith. The one-shot method is a preferable method because the manufacturing process is one step compared to the prepolymer method, and there are few restrictions on the manufacturing conditions, and the manufacturing cost can be reduced.

  A polyurethane foam having an open-cell structure can be obtained by appropriately adjusting the blending of raw materials during the production of the polyurethane foam. And it is preferable that it is an open-cell type, since the sound absorption performance of sucking sound into the cell can be exhibited. In the case of the closed cell type structure, sound is reflected on the surface of the polyurethane foam and hardly absorbed in the cell.

  When the polyurethane foam sheet-like product 10 is manufactured, as shown in FIG. 1, the resin film 12 is fed from the feed roller 14, and the polyurethane foam raw material is fed from the raw material supply device 17 onto the resin film 12. 15 is supplied. On the other hand, at the upper position, the release film 19 is supplied from the delivery roller 18 so as to be superimposed on the raw material 15, and the resin film 12 and the release film are held in a state where the raw material 15 is sandwiched by being pressed by the pressing roller 20. The thickness between 19 is adjusted to 1 mm, for example.

  Next, the raw material 15 is naturally foamed while being kept at 30 ° C. in the primary heating furnace 21 to form a foam. Subsequently, the polyols and polyisocyanates in the raw material 15 are reacted and cured by heating in the secondary heating furnace 22 set to 80 ° C. In this production process, a polyether polyol having a primary hydroxyl group at the terminal is mainly used as a polyol, so that the reactivity of the resinification reaction is higher than that of a polyether polyol having a secondary hydroxyl group. The structure becomes dense, and the strength at the end face of the sheet-like product can be secured. In addition, since a temperature-sensitive catalyst such as DBU or DBN is used as the catalyst, the resinification reaction proceeds gradually and uniformly as the temperature rises as compared with a normal amine catalyst.

  Thereafter, the release film 19 is taken up by the take-up roller 26, and the sheet-like product 10 in which the resin film 12 is bonded to the lower surface of the polyurethane foam sheet 11 is continuously fed forward while being supported by the support roller 25. It is done.

The effects exhibited by the above embodiment will be described collectively below.
-In the manufacturing method of the sheet-like product 10 of this embodiment, the polyether polyol which has a primary hydroxyl group at the terminal as a polyol and the ratio is 50 mass% or more is used. The primary hydroxyl group bonded to the end of the polyether polyol has good reactivity of the resinification reaction, ensures the strength at the end of the polyurethane foam, and suppresses powder falling off at the end face of the sheet-like product 10. it can. Further, since the temperature-sensitive catalyst is used as the catalyst, the resinification reaction proceeds uniformly as a whole, and the change in the thickness of the sheet-like product 10 can be suppressed. Therefore, the sheet-like product 10 which has the said effect can be manufactured easily by selecting the polyols and catalyst in the raw material of a polyurethane foam as mentioned above.

  -Since the polyether polyol is a triol obtained by adding propylene oxide and ethylene oxide to a trihydric alcohol, the crosslinking density of the polyurethane foam can be increased and the strength can be increased. Therefore, powder fall off at the end face of the sheet-like product 10 can be further suppressed.

  -Since the temperature-sensitive catalyst is a diazabicycloalkene or a salt thereof, it is sensitive to temperature and excellent in temperature sensitivity. Therefore, the thickness change of the sheet-like product 10 can be further suppressed.

  The surface of the sheet-like product 10 is formed by placing the release film 19 on the polyurethane foam raw material, reacting polyols and polyisocyanates, foaming and curing, and then peeling the release film 19. A cured film is formed on the part to smooth the surface. In addition, in the process of manufacturing the sheet-like product 10, it can be avoided that the polyurethane foam raw material 15 adheres to, for example, the press roller 20 and causes a problem.

  -By using the sheet-like product 10 as a gasket for electronic equipment, when manufacturing a gasket for electronic equipment, there is no powder falling off at the end face, and the change in thickness can be suppressed, and the gasket is easily manufactured. can do.

When the obtained sheet-like product 10 is used by being inserted in a compressed state between the main body of the hard disk drive and the substrate, for example, it is constituted by an open cell type flexible polyurethane foam, so that the closed cell Compared with, sound is effectively absorbed in the open bubbles, and the sound absorption can be improved. Further, a resin film 12 is adhered to one side of the sheet-like product 10, the surface density (kg / m ² ) is increased, the Young's modulus is increased, the propagation of vibration is suppressed, and the sound absorption is further enhanced. be able to. In addition, a film made of a heat-cured product of polyurethane foam is formed on the surface of the polyurethane foam sheet 11, and the propagation of vibrations can be suppressed by the film, thereby further improving sound absorption.

Hereinafter, the embodiment will be described in more detail with reference to examples and comparative examples, but the invention is not limited to these examples.
(Examples 1-6 and Comparative Examples 1-4)
As a raw material of the polyurethane foam, one having the composition shown in Table 1 was prepared, and a polyethylene terephthalate (PET) film (thickness 50 μm) as a resin film 12 on one surface of the polyurethane foam sheet 11 by the manufacturing apparatus shown in FIG. 1) to produce a sheet-like product 10 having a thickness of 1 mm. In this case, the clearance between the presser roller 20 and the apparatus main body 13 (the portion indicated by the two-dot chain line in FIG. 1) is 1 mm, the temperature of the primary heating furnace 21 is 30 ° C., and the temperature of the secondary heating furnace 22 is 80 ° C. .

  Here, in Comparative Example 1, the polyether polyol as a raw material for the polyurethane foam does not have a terminal primary hydroxyl group and does not contain a temperature-sensitive catalyst. In Comparative Example 2, the polyether polyol has a terminal primary hydroxyl group as a polyether polyol. The example which used what is not is shown. Comparative Example 3 shows an example in which the proportion of terminal primary hydroxyl groups as the polyether polyol is less than 50% by mass (48% by mass), and Comparative Example 4 shows an example that does not contain a temperature-sensitive catalyst.

  About the obtained sheet-like product 10, the result of apparent density, the change of thickness, and the powder fall of the end surface was measured by the method described below, and the results are shown in Table 1. The meanings of the abbreviations in Table 1 are shown below.

Apparent density (kg / m ³ ): Measured according to JIS K7222: 1999.
Change in thickness: 200m continuous production of sheet-like product 10 (50 minutes at a line speed of 4m / min), and the thickness at the start of production (t0) and the thickness at the end of production (t1) are measured. , Δt = [(t1−t0) / t0] × 100 was calculated. And, when Δt> 10%, ×, and when Δt ≦ 10%, it was evaluated as ◯.

End face powder fall: The sheet-like product 10 was punched with a dumbbell No. 1 Thomson type of JIS K6400, and the end face powder fall was visually observed. And when powder fall was observed, it was set to x, and when powder fall was not observed, it was set as (circle).
(Abbreviations in Table 1)
Polyether polyol GP3000: polyether polyol manufactured by Sanyo Chemical Industries, Ltd., molecular weight 3000, hydroxyl value 56 mgKOH / g, triol obtained by addition polymerization of propylene oxide to glycerin, and the ratio of terminal primary hydroxyl group is 0% by mass.

  Polyether polyol FA703: polyether polyol manufactured by Sanyo Chemical Industries, Ltd., molecular weight 5000, hydroxyl value 35 mgKOH / g, triol obtained by addition polymerization of propylene oxide and ethylene oxide to glycerin, and the proportion of terminal primary hydroxyl group is 80% by mass.

  Polyether polyol PML7001K: polyether polyol manufactured by Asahi Glass Co., Ltd., molecular weight 6500, hydroxyl value 28 mgKOH / g, triol obtained by addition polymerization of propylene oxide and ethylene oxide to trimethylolpropane, and the proportion of terminal primary hydroxyl group is 90% by mass.

Polyisocyanate SBU0379: 4,4-diphenylmethane diisocyanate (MDI) prepolymer manufactured by Sumitomo Bayer Co., Ltd., 25% by mass of isocyanate groups.
Thermosensitive catalyst U-catSA1: DBU phenol salt manufactured by San Apro Co., Ltd.

Thermosensitive catalyst U-cat SA102: DBU octylate manufactured by San Apro Co., Ltd.
Temperature-sensitive catalyst U-cat1102: DBN octylate manufactured by San Apro Co., Ltd.
Metal catalyst MRH110: stannous octylate manufactured by Johoku Chemical Co., Ltd.

Amine catalyst kaolinizer No. 1: Tertiary amine manufactured by Kao Corporation.
Flame retardant: Mixture of 20 parts by mass of melamine powder manufactured by Mitsui Chemicals and 10 parts by mass of flame retardant SH800 manufactured by Daihachi Chemicals.

  Antistatic agent cation IN: an antistatic agent manufactured by Nippon Oil & Fats Co., Ltd.

表１に示す結果より、実施例１〜６では、シート状製品１０の厚さの変化がなく、かつ端面の粉落ちが認められなかった。これは、いずれの実施例においても、ポリエーテルポリオールは末端一級水酸基の割合が５０質量％以上であり、かつ触媒として感温性触媒を用いたことから、シート状製品１０の製造過程で樹脂化反応が安定した状態で、均一に進行し、緻密な発泡体が形成されたものと考えられる。

From the result shown in Table 1, in Examples 1-6, there was no change of the thickness of the sheet-like product 10, and the powder fall of the end surface was not recognized. In any of the examples, the polyether polyol has a terminal primary hydroxyl group ratio of 50% by mass or more and a temperature-sensitive catalyst is used as a catalyst. It is considered that the reaction proceeded uniformly and a dense foam was formed in a stable state.

  On the other hand, in Comparative Example 1, since the polyether polyol does not have a terminal primary hydroxyl group and does not contain a temperature-sensitive catalyst, the thickness of the sheet-like product changes by more than 10% compared to the production start time, Moreover, powder falling off of the end face was observed. In Comparative Example 2, since a polyether polyol having no terminal primary hydroxyl group was used, end face powdering was observed. In Comparative Example 3, since the proportion of the terminal primary hydroxyl group as the polyether polyol was less than 50% by mass, powder falling off of the end face was observed. In Comparative Example 4, since no temperature-sensitive catalyst was contained, powder falling off of the end face was observed, and the thickness of the sheet-like product 10 was changed by more than 10% as compared with that at the start of production.

It should be noted that the embodiment described above can be modified and embodied as follows.
In the manufacturing apparatus for the polyurethane foam sheet-like product 10, the primary heating furnace 21 and the secondary heating furnace 22 of the apparatus body 13 can be integrated, and the length of each heating furnace can be changed by changing the heating temperature setting. It may be configured so that it can be easily changed.

  In the manufacturing apparatus for the polyurethane foam sheet product 10, the resin film 12 is wound instead of the release film 19 wound around the delivery roller 18, and the resin film 12 is placed on both surfaces of the polyurethane foam sheet 11. It can also be glued.

  It is also possible to manufacture only the polyurethane foam sheet 11 and apply an adhesive such as polyurethane adhesive on one or both sides of the sheet 11 to adhere the resin film 12. Alternatively, for example, a soft slab polyurethane foam may be used as the polyurethane foam, cut out into a sheet shape, and then a resin film may be adhered to the surface to produce the sheet-like product 10. The soft slab polyurethane foam is obtained by discharging a raw material onto a belt conveyor, and naturally foaming the raw material at normal temperature and atmospheric pressure while the belt conveyor moves, and then curing (curing) in a drying furnace.

The polyurethane foam sheet 11 can also be manufactured by a molding method or the like.
The post-curing (after-cure) can also be performed on the sheet-like product 10 that has come out of the secondary heating furnace 22 in a different heating furnace in a separate batch process.

Further, the technical idea that can be grasped from the embodiment will be described below.
6. The polyurethane foam sheet-like product according to any one of claims 1 to 5, wherein a film of a polyurethane foam cured product is formed on a surface of the sheet. Method. When comprised in this way, the surface of a sheet-like product can be made smooth by the high-density film | membrane which exists on the surface of a sheet-like product.

  The sheet material is continuously manufactured by moving the resin film continuously and continuously supplying the raw material onto the resin film. The manufacturing method of the sheet-like product of the polyurethane foam as described in a term. According to this manufacturing method, the productivity of a polyurethane foam sheet-like product can be improved.

  The said foaming agent is water, The manufacturing method of the sheet-like product of the polyurethane foam as described in any one of Claims 1-5 characterized by the above-mentioned. According to this manufacturing method, the reactivity of the foaming reaction is excellent, and the handling of the foaming agent can be improved.

  The said polyisocyanate is a polymer of 4, 4- diphenylmethane diisocyanate, The manufacturing method of the sheet-like product of the polyurethane foam as described in any one of Claims 1-5 characterized by the above-mentioned. According to this manufacturing method, the structure of the polyurethane foam can be made denser, powder falling at the end face can be further suppressed, and the change in thickness can be further suppressed.

The schematic sectional drawing which shows the manufacturing apparatus of the sheet-like product of the polyurethane foam in embodiment. The schematic sectional drawing which shows the sheet-like product of the polyurethane foam in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Sheet-like product, 11 ... Sheet of polyurethane foam, 12 ... Resin film, 15 ... Raw material of polyurethane foam, 19 ... Release film.

Claims (5)

Polyurethane foam raw materials containing polyols, polyisocyanates, catalyst and foaming agent are supplied on the resin film, the polyols and polyisocyanates are reacted, foamed and cured to form polyurethane foam sheets. In producing a polyurethane foam sheet-like product having a resin film adhered to the sheet, a polyether polyol having a primary hydroxyl group at the terminal and a proportion of 50% by mass or more is used as the polyol. A method for producing a polyurethane foam sheet product, wherein a temperature-sensitive catalyst is used as the catalyst. The method for producing a sheet product of polyurethane foam according to claim 1, wherein the polyether polyol is a triol obtained by adding propylene oxide and ethylene oxide to a trihydric alcohol. The method for producing a sheet product of polyurethane foam according to claim 1 or 2, wherein the temperature-sensitive catalyst is diazabicycloalkene or a salt thereof. The release film is peeled off after placing a release film on the raw material of the polyurethane foam, reacting polyols and polyisocyanates, foaming and curing, and then releasing the release film. 4. A method for producing a sheet product of polyurethane foam according to any one of 3 above. The polyurethane foam sheet-like product according to any one of claims 1 to 4, wherein the polyurethane foam sheet-like product is used as a gasket for an electronic device. Method.

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